My invention relates to a method and an apparatus for separating toxic components from gaseous mixtures, and more particularly to a method and a portable apparatus for the continuous removal of fluorine and compounds thereof from gaseous mixtures.
It is well known that compounds of fluorine attack and have a corrosive effect upon metal parts or surfaces exposed thereto. Pitting of such parts and surfaces may result from prolonged exposure. Protection of plant equipment from these effects may be accomplished by forming a thin protective fluoride coating on the exposed surfaces and parts, either by circulating concentrated fluorine for a predetermined short period through the system, or by subjecting the parts or surfaces to dilute concentrations of fluorine for a sufficient period of time to effect reaction with the metal surfaces. The concentration of fluorine may be controlled by mixing it with some inert gas, such as nitrogen, and passing the mixture through the various units of the system or plant. It may be purged from the unit with nitrogen or other inert gas. The purged gas mixtures, however, cannot be exhausted to the atmosphere in substantial quantities since fluorine and its gaseous compounds are present therein. Under these circumstances it is important to provide for the disposal of such excess fluorine. Despite the great reactivity of this gas, means of disposal are quite limited. The matter of disposal is important, not only from the health standpoint but also for psychological reasons. Not only are persons in the vicinity annoyed by low concentrations of gas, but winds can carry the gas for long distances and it can affect fruit and other crops as well as grass and trees, the extent of damage being a function of concentration and time.
Where a number of conditioning units are involved, particularly where they are separated or cover a considerable area, it may be necessary to provide portable equipment for disposing of the fluorine content of the purged gases instead of going to the expense of installing a central disposal plant and piping the gases from the various units over considerable distances thereto. Even where such a central disposal plant is employed it may be necessary to have portable equipment in reserve to insure uninterrupted operation of the conditioning plant in the event of failure of the central plant.
Various ways have been suggested in the prior art for removing certain components from gaseous mixtures. Absorption of acidic gases in alkaline solutions is illustrated in the patents to Claude, U.S. Pat. No. 1,717,761; Bottoms, U.S. Pat. No. 1,834,016; Stelzmer, U.S. Pat. No. 1,860,298; Brogg, U.S. Pat. No. 1,920,626 and Bottoms, U.S. Pat. No. Re 18958. A precipitation method for fluorine removal is illustrated in Weber, U.S. Pat. No. 2,231,309. The use of liquid absorbents is undesirable in portable equipment in view of the large volumes of liquids which are necessary, the pumping requirements, and the danger of liquid backing up into the equipment being purged. Precipitation procedures are not well adapted to either a continuous process or for portable equipment. Steps involving precipitation are best suited to batch processes where large bulky tanks and other plant facilities are available. In a continuous process the precipitate would tend to clog the valves and circulating system, and in addition, settling tank capacity would be required.
Applicant with a knowledge of these problems in the prior art has for an object of his invention the provision of a portable apparatus for the removal of fluorine values from gaseous mixtures.
Applicant has as another object of his invention the provision of a continuous process for the removal of fluorine values from gaseous mixtures.
Applicant has as another object of his invention the treatment of waste gases containing fluorine values with a highly reactive agent to remove the fluorine values therefrom.
Applicant has as a further object of his invention the provision of an agent which may be employed in solid concentrated form and in relatively small volume to treat waste gases for removing fluorine values therefrom, lending itself to use in systems of portable character.
Applicant has as a still further object of his invention the provision of an agent for removing fluorine values from waste gases which is available in quantity and cheap in price, and which may be easily prepared in useful form.